feature<Histories>: show avatars in histories

src/Helpers/Avatar.cs

@@ -0,0 +1,185 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+
+namespace SourceGit.Helpers {
+
+    /// <summary>
+    ///     Avatar control
+    /// </summary>
+    public class Avatar : Image {
+
+        /// <summary>
+        ///     Colors used in avatar
+        /// </summary>
+        public static Brush[] Colors = new Brush[] {
+            Brushes.DarkBlue,
+            Brushes.DarkCyan,
+            Brushes.DarkGoldenrod,
+            Brushes.DarkGray,
+            Brushes.DarkGreen,
+            Brushes.DarkKhaki,
+            Brushes.DarkMagenta,
+            Brushes.DarkOliveGreen,
+            Brushes.DarkOrange,
+            Brushes.DarkOrchid,
+            Brushes.DarkRed,
+            Brushes.DarkSalmon,
+            Brushes.DarkSeaGreen,
+            Brushes.DarkSlateBlue,
+            Brushes.DarkSlateGray,
+            Brushes.DarkTurquoise,
+            Brushes.DarkViolet
+        };
+
+        /// <summary>
+        ///     User property definition.
+        /// </summary>
+        public static readonly DependencyProperty UserProperty = DependencyProperty.Register(
+            "User", 
+            typeof(Git.User), 
+            typeof(Avatar), 
+            new PropertyMetadata(null, OnUserChanged));
+
+        /// <summary>
+        ///     User property
+        /// </summary>
+        public Git.User User {
+            get { return (Git.User)GetValue(UserProperty); }
+            set { SetValue(UserProperty, value); }
+        }
+
+        /// <summary>
+        ///     Loading request
+        /// </summary>
+        private class Request {
+            public BitmapImage img = null;
+            public List<Avatar> targets = new List<Avatar>();
+        }
+
+        /// <summary>
+        ///     Path to cache downloaded avatars
+        /// </summary>
+        private static readonly string CACHE_PATH = Path.Combine(
+            Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
+            "SourceGit",
+            "avatars");
+
+        /// <summary>
+        ///     Current requests.
+        /// </summary>
+        private static Dictionary<string, Request> requesting = new Dictionary<string, Request>();
+
+        /// <summary>
+        ///     Render implementation.
+        /// </summary>
+        /// <param name="dc"></param>
+        protected override void OnRender(DrawingContext dc) {
+            base.OnRender(dc);
+
+            if (Source == null && User != null) {
+                var placeholder = User.Name.Length > 0 ? User.Name.Substring(0, 1) : "?";
+                var formatted = new FormattedText(
+                    placeholder,
+                    CultureInfo.CurrentCulture,
+                    FlowDirection.LeftToRight,
+                    new Typeface(new FontFamily("Consolas"), FontStyles.Normal, FontWeights.Normal, FontStretches.Normal),
+                    Width * 0.75,
+                    Brushes.White,
+                    VisualTreeHelper.GetDpi(this).PixelsPerDip);
+
+                double offsetX = 0;
+                if (HorizontalAlignment == HorizontalAlignment.Right) {
+                    offsetX = -Width * 0.5;
+                }
+
+                var chars = placeholder.ToCharArray();
+                var sum = 0;
+                foreach (var ch in chars) sum += Math.Abs(ch);
+                var brush = Colors[sum % Colors.Length];
+
+                dc.DrawRoundedRectangle(brush, null, new Rect(-Width * 0.5 + offsetX, -Height * 0.5, Width, Height), Width / 16, Height / 16);
+                dc.DrawText(formatted, new Point(formatted.Width * -0.5 + offsetX, formatted.Height * -0.5));
+            }
+        }
+
+        /// <summary>
+        ///     Reset image.
+        /// </summary>
+        private void ReloadImage(Git.User oldUser) {
+            if (oldUser != null && requesting.ContainsKey(oldUser.Email)) {
+                if (requesting[oldUser.Email].targets.Count <= 1) {
+                    requesting.Remove(oldUser.Email);
+                } else {
+                    requesting[oldUser.Email].targets.Remove(this);
+                }
+            }
+
+            Source = null;
+            InvalidateVisual();
+
+            if (User == null) return;
+
+            var email = User.Email;
+            if (requesting.ContainsKey(email)) {
+                requesting[email].targets.Add(this);
+                return;
+            }
+
+            byte[] hash = MD5.Create().ComputeHash(Encoding.Default.GetBytes(email.ToLower().Trim()));
+            string md5 = "";
+            for (int i = 0; i < hash.Length; i++) md5 += hash[i].ToString("x2");
+            md5 = md5.ToLower();
+
+            string filePath = Path.Combine(CACHE_PATH, md5);
+            if (File.Exists(filePath)) {
+                Source = new BitmapImage(new Uri(filePath));
+                return;
+            }
+
+            requesting.Add(email, new Request());
+            requesting[email].targets.Add(this);
+
+            BitmapImage downloading = new BitmapImage(new Uri("https://www.gravatar.com/avatar/" + md5 + "?d=404"));
+            requesting[email].img = downloading;
+            downloading.DownloadCompleted += (o, e) => {
+                var owner = o as BitmapImage;
+                if (owner != null) {
+                    if (!Directory.Exists(CACHE_PATH)) Directory.CreateDirectory(CACHE_PATH);
+
+                    var encoder = new PngBitmapEncoder();
+                    encoder.Frames.Add(BitmapFrame.Create(owner));
+                    using (var fs = new FileStream(filePath, FileMode.Create)) {
+                        encoder.Save(fs);
+                    }
+
+                    if (requesting.ContainsKey(email)) {
+                        BitmapImage exists = new BitmapImage(new Uri(filePath));
+                        foreach (var one in requesting[email].targets) one.Source = exists;
+                        requesting.Remove(email);
+                    }
+                }
+            };
+            downloading.DownloadFailed += (o, e) => {
+                requesting.Remove(email);
+            };
+        }
+
+        /// <summary>
+        ///     Callback on user property changed
+        /// </summary>
+        /// <param name="d"></param>
+        /// <param name="e"></param>
+        private static void OnUserChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
+            Avatar a = d as Avatar;
+            if (a != null) a.ReloadImage(e.OldValue as Git.User);
+        }
+    }
+}